Gas-fired radiant heater

ABSTRACT

A GAS-FIRED RADIANT HEATER ASSEMBLY HAVING A PLURALITY OF POROUS CERAMIC TILES FORMING A RADIANT GAS BURNING SURFACE IN WHICH THE TILES ARE SUPPORTED ON TWO PARALLEL SPACED LONGITUDINALLY EXTENDING METAL SHELVES OF Z CROSS SECTIONAL SHAPE WITH THE DEPENDING LEG OF EACH SHELF HAVING A PLURALITY OF SPACED APART STRESS RELIEVING NOTCHES HAVING THEIR OPENINGS DIRECTED AWAY FROM THE HOT RADIANT SIDE OF THE TILE MEMBERS SUPPORTED ON THE SHELVES. EACH SUPPORT SHELF IS SECURED TO A RESPECTIVE LONG SIDE OF A RECTANGULAR FRAME MEMBER THAT IS REMOVABLY ATTACHED TO THE OPENING OF THE HEATER BODY.

11111.19, 1971 I I I L-P.HINE,J 3,556,707

GAS-FIRED RADIANT HEATER Filed June 5, 1969 INVENTOR Lo uis P. Hine Jr.

ATTORNEY United States Patent 3,556,707 I GAS-FIRED RADIANT HEATER I Louis P. Hine, Jr., Elyria, Ohio, assignor to Luxaire, Inc.,

Elyria, Ohio, a corporation of Delaware Filed June 5, 1969, Ser. No. 830,660 Int. Cl. F2311 13/12 U.S. Cl. 431-328 V 6 Claims ABSTRACT on THE DISCLOSURE CROSS REFERENCESTO RELATED APPLICATIONS member portions of the shelves. A reverberator grid of suitable heat reflecting metal rods is secured to the rectangular frame in spaced relation to the radiant surface of the ceramic tiles. The ceramic tiles are separated from each other by respective resilient sealing gasket strips of matted ceramic fiber material. In the preferred form of the invention, the tile support shelves are formed of a metal having a low creep characteristic such as certain types of stainless steel, i.e., stainless steel numbers 442 or 446. Also the reverberator screen may be formed of similar low creep characteristic metal since it has been discovered that the scale forming on such metal with usage does not tend to flake on as readily as with other metal materials.

Further objects, features and the attendant advantages of the invention will be apparent with reference to the following specification and drawing.

BRIEF DESCRIPTION OF THE DRAWING So far as is known, this applicationisnotrelated to any copending patent applications.,, t

BACKGROUND OF TH INVENTION I Gas fired radiant heaters for space heating purposes are well known. Many. ditferenttypes ofuradiant gas burning surfaces are used such as metal screens orporous ceramic tiles. A problem .with the .use of ceramic tile gas burning radiant surfacesis concerned with the manner of supporting the tiles on the metalstructures forming the heater housing or body considering the comparatively which are more closely adjacentthe back non-radiant side of the tiles giving rise to mech anicallstresses resulting in undesired distortions and deformations of thememl parts of the heater body. i

PRIOR ART There are many patents disclo sing a fire da'diain heaters with porous ceramicdiles form ng the radiant burning surfaces. None of the, prior patents ,known to applicant discloses the particular stress relievirrg arrangeg ments of this invention. v I I SUMMARY t In accordance with the invention, the 'g'asfired'radiant heater assembly is comprisedof a heater ma preferably formed of sheet metal which has an open"si'de 'adaptedto be closed with a plurality of porous ceramic tile members to form a radiant gas burning surfaee'A generally rectangular tile support frame 'is femovably secured to the burner body about its open side 'andthe width of the frame, i.e., its shorter side is slightly greater than'the width of the ceramic tiles to permit'expansion and contraction movement of thetiles in that direction. Each parallel long side memberof-theframe is provided with a respective metal tile support shelf member of'Z cross section secured to the inner sidethere'of and the 'depending leg of each shelf member is provided with 'a' plurality of spaced apart stress relieving notches havingtheir' openings directed away from the radiant hot side of the ceramic tile members supported on the intermediate 'shelf support frame as secured to the open side of the heater body.

DEscRIPnoNoE THE PREFERRED EMBODIMENT Referring to the drawing, the heater body which is preferably formed of sheet metal is shown at 10 to have an open side bounded by flanges such as the flanges 11 and -12 which are the flanges extending along the long side of the generally rectangular heater body. Flanges on the short sides of the heater body 10 are not shown. It will be understood that various plenum arrangements for in- .troducing combustible mixtures of gas and air to the in- .terior of the body 10 may be used as are well known in the art and since this invention is not concerned with 'manner to close the open side of the heater body 10and 'provide a radiant gas burning surface such as shown at 17. It will be noted that the width between the generally parallel long side members 18 and 19 of the rectangular frame '14 is slightly greater than the widths of the tiles 20 and 21 so as to provide open spaces 22 and 23 for the expansion and contraction of the ceramic tiles in that direction.

Each long side member 18 and 19 of the rectangular frame 14 is provided with a respective tile supporting shelf member 26, 27 having a Z-shaped cross section so as to form a tile supporting shelf by the intermediate portion of the respective shelf support member. The metal support shelves 26, 27 may be secured to the inner sides of the respective longitudinal frame members 18 and 19 by spot'welding or the like (not shown).

In the absence of the stress relieving features of the invention now to be described, the parallel supporting shelf members 26, 27 would have portions closely ad- 'jacent to the radiant surfaces of the tile supported therestresses, a plurality of spaced apart notches such as the notches 30 and 31 are formed in the depending leg portions 32, 33 of the respective tile support members 26 and 27. It has been found that the provision of these spaced apart notches 30, 31, etc. with their openings facing away from the hot radiant surfaces of the tiles 15, 16-, etc. enable the differential expansions and contractions of the various portions of the Z-shaped supporting shelves 26 and 27 to take place without inducnig undesired mechanical stresses in the frame side members to which they are secured. In the preferred form of the invention each of the Z-shaped tile supporting shelves 26, 27 is formed of a metal having a low creep characteristic such as stainless steel numbers 442 or 446. As is known to those skilled in the art a low creep characteristic metal is a metal which acquires a minimum of change in its dimensions over a period of time involving many cycles of contractions and expansions due to cooling and heat- Another feature of the invention is the provision of a metal reverberator screen such as generally shown at 40 to be loosely positioned over the inwardly extending flange portions 41 and 42 of the long members 18 and 19 of the rectangular frame 14. Thus the spaced position of the reverberator screen 40 is accurately predetermined with relatiton to the radiant surfaces such as the surface 17 of the respective ceramic tiles 15, 16, etc. In the preferred form of the invention, the reverberator screen is formed of low creep stainless steel numbers 442 or 446, which in view of their low creep characteristics have been found to have a minimum tendency for scale flaking during extended periods of operation.

Expansion of the ceramic tiles, such as the tiles 15, 16 in the long direction of the heated body is provided for by a plurality of resilient sealing gaskets such as the gaskets shown at 50 and 51. A preferred form of material for the gaskets 50 and 51. is a matted ceramic fiber gasket material of which there are a number of types commercially available and well known to those skilled in the art. In securing the rectangular tile supporting frame 14- to the heater body 10, an asbestos gasket sealing strip material such as shown at 52 and 53 may be interposed between the abutting flanges of the frame 14 and the body as shown. Thus each of the ceramic tiles and 16 is supported in sealed relation to the opening of the heater body 10 in a manner to permit movement of either tile member in all directions due to expansion and contraction in operation and the specific tile support shelf members are fashioned in such manner as to relieve any mechanical stresses during operation so that the heater body and the tile supporting frame will not be distorted or buckled.

of the long side members of the frame having a respective metal shelf secured to the inner sides thereof with a substantially Z-shaped cross section and adapted to support said tiles on the intermediate shelf portions thereof, the depending leg of each shel-f having a plurality of spaced apart notches with their openings directed away from the radiant side of the tile members supported on the respective support shelves to thereby permit expansion and contraction of the support shelves in a manner to reduce induced mechanical stresses in said rectangular support frame.

2. The invention of claim 1 in which a reverberator grid is supported by said support frame in predetermined spaced relation to the radiant surface of the tiles supported on said support shelves. 4

3. The invention of claim 1 in which a resilient matted ceramic fiber gasket is interposed in sealing relation extending from one support shelf to the other support shelf between adjacent ceramic tiles.

4. The invention of claim 2 in which a resilient matted ceramic fiber gasket is interposed in sealing relation extending from one support shelf to the other support shelf between adjacent ceramic tiles.

5. The invention of claim 1 in which each of said support shelves is comprised of a metal having a low creep characteristic.

6. The invention of claim 5 in which the reverberator grid is formed of metal with a low creep characteristic.

References Cited UNITED STATES PATENTS 2,633,190 3/1953 Kerwin et a1. 3,114,410 12/ 1963 Schneider. 3,291,115 12/1966 Forniti.

FOREIGN PATENTS 1,204,352 11/1965 Germany.

FREDERICK L. MATTESON, Primary Examiner H. B. RAMEY, Assistant Examiner 

